Keeping Up With Technology

GE's New Plastic Is a TP Polyimide

From: Plastics Technology
Issue: December 2006

Extem is the name of the new thermoplastic polyimide (TPI) family announced this month by GE Plastics, Pittsfield, Mass.

Extem is the name of the new thermoplastic polyimide (TPI) family announced this month by GE Plastics, Pittsfield, Mass. Commercial quantities will be available in February or March from a U.S. semi-works plant. As reported last month, large-scale production will begin in 2008 at a plant being built in Spain. A cousin to GE's Ultem polyetherimide, Extem is a brand-new, fully amorphous polymer with similar processability but much greater heat resistance-i.e., glass-transition temperature (Tg) up to 311 C and continuous use at up to 230 C. Its Tg is higher than that of Aurum TPI from Mitsui Chemicals America, but Aurum boasts higher continuous-use temperatures. GE claims improved resistance to chlorinated solvents, such as methylene chloride, for Extem. GE also says Extem has better creep resistance and dimensional stability under load at high temperatures than other high-end crystalline thermoplastics like PPS and PEEK. Also, it can be molded and extruded on standard equipment and requires no post-curing or heat treatment to achieve its full properties, unlike Solvay's Torlon polyamide-imide. Extem is also transparent and inherently flame retardant (45 LOI). Two families will be initially available-Extem UH with maximum heat and chemical resistance, and Extem XH with better flow. GE sees applications in underhood auto parts, aerospace and military uses, down-hole oil and gas production, medical membranes, electrical connectors, electronics for lead-free soldering, semiconductor wafer handling, and specialty films for insulators and flexible circuitry. Initial price is in the range of $27 to $45/lb, or around $18/lb in blends with Ultem.